Data commit

Task/Bitmap-Midpoint-circle-algorithm/Nim/bitmap-midpoint-circle-algorithm-1.nim

@@ -0,0 +1,49 @@
+import bitmap
+
+proc setPixel(img: Image; x, y: int; color: Color) {.inline.} =
+  # Set a pixel at a given color.
+  # Ignore if the point is outside of the image.
+  if x in 0..<img.w and y in 0..<img.h:
+    img[x, y] = color
+
+
+proc drawCircle(img: Image; center: Point; radius: Natural; color: Color) =
+  ## Draw a circle using midpoint circle algorithm.
+
+  var
+    f = 1 - radius
+    ddFX = 0
+    ddFY = -2 * radius
+    x = 0
+    y = radius
+
+  img.setPixel(center.x, center.y + radius, color)
+  img.setPixel(center.x, center.y - radius, color)
+  img.setPixel(center.x + radius, center.y, color)
+  img.setPixel(center.x - radius, center.y, color)
+
+  while x < y:
+    if f >= 0:
+      dec y
+      inc ddFY, 2
+      inc f, ddFY
+    inc x
+    inc ddFX, 2
+    inc f, ddFX + 1
+
+    img.setPixel(center.x + x, center.y + y, color)
+    img.setPixel(center.x - x, center.y + y, color)
+    img.setPixel(center.x + x, center.y - y, color)
+    img.setPixel(center.x - x, center.y - y, color)
+    img.setPixel(center.x + y, center.y + x, color)
+    img.setPixel(center.x - y, center.y + x, color)
+    img.setPixel(center.x + y, center.y - x, color)
+    img.setPixel(center.x - y, center.y - x, color)
+
+#———————————————————————————————————————————————————————————————————————————————————————————————————
+
+when isMainModule:
+  var img = newImage(16, 16)
+  img.fill(White)
+  img.drawCircle((7, 7), 5, Black)
+  img.print()

Task/Bitmap-Midpoint-circle-algorithm/Nim/bitmap-midpoint-circle-algorithm-2.nim

@@ -0,0 +1,27 @@
+let raster_circle ~img ~color ~c:(x0, y0) ~r =
+  let plot = put_pixel img color in
+  let x = 0
+  and y = r
+  and m = 5 - 4 * r
+  in
+  let rec loop x y m =
+    plot (x0 + x) (y0 + y);
+    plot (x0 + y) (y0 + x);
+    plot (x0 - x) (y0 + y);
+    plot (x0 - y) (y0 + x);
+    plot (x0 + x) (y0 - y);
+    plot (x0 + y) (y0 - x);
+    plot (x0 - x) (y0 - y);
+    plot (x0 - y) (y0 - x);
+    let y, m =
+      if m > 0
+      then (y - 1), (m - 8 * y)
+      else y, m
+    in
+    if x <= y then
+      let x = x + 1 in
+      let m = m + 8 * x + 4 in
+      loop x y m
+  in
+  loop x y m
+;;